The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An automatic transmission for a motor vehicle generally includes a number of gear elements and torque establishing devices such as clutches and brakes. The clutches and brakes are selectively engageable to activate certain gear elements to establish a desired speed ratio between a transmission input shaft and a transmission output shaft.
The transmission input shaft is connected to an engine through a fluid coupling such as a torque converter. The transmission output shaft is connected to vehicle wheels. Gear shifting from one forward speed ratio to another may be performed in response to changes in throttle opening and vehicle speed.
In a typical automatic transmission while accelerating the vehicle, when a driver lifts his/her foot off of the accelerator pedal, an upshift to a higher gear may be triggered. If the driver then depresses the accelerator pedal during an upshift to resume acceleration, a downshift for vehicle acceleration may be commanded. This downshift may not be executed until the upshift is completed. As a result, the acceleration may be delayed.
In a typical automatic transmission, while decelerating the vehicle during a coast down (with a driver's foot off the accelerator pedal), a closed throttle downshift may be triggered. If the driver then depresses the accelerator pedal during the closed throttle downshift to accelerate, a downshift for acceleration may be commanded. This downshift may not be executed until the closed throttle downshift is completed. As a result, the acceleration may be delayed.